Advancing Marine Sanctuary Management with USVs: Optical Sensor Integration for Monitoring Ecosystems in Palau

Autonomous platforms are increasingly critical for sustained monitoring of remote marine environments, where traditional ship-based sampling is logistically limited and costly. Between January 2024 and April 2025, a Boeing Liquid Robotics Wave Glider uncrewed surface vehicle (USV) operated for 360 days in Palau's National Marine Sanctuary to assess persistent observational strategies for ecosystem variability. Central to this mission was the integration of an optical sensor pack-age, protected against biofouling and mounted on the vehicle's skeg, to capture high-resolution measurements of chlorophyll-a fluorescence, particulate backscatter, and fluorescent dissolved organic matter (fDOM). These optical proxies offer insight into phytoplankton biomass and biogeochemical gradients. Data acquisition and real-time transmission were enabled by a Robot Operating System (ROS)-based onboard computing system, sup-porting fully autonomous operations. The optical dataset was contextualized using satellite observations from Ocean and Land Color Instrument (OLCI) on Sentinel-3 and surface current fields from High-Frequency radar. Chlorophyll variability is influenced by large-scale seasonal patterns associated with the migration of the North Equatorial Countercurrent (NECC), along with fine-scale spatial structures related to island wake dynamics, key processes associated with the Island Mass Effect. This integration of hardware, software, and multi-platform sensing demonstrates the potential of autonomous systems for persistent ecosystem monitoring in support of fisheries management and large marine protected areas.